Shalom, I don't know if the Lubavitcher Rebbe is Moshiach. When the Lubavitcher Rebbe was asked if he is Moshiach, he replied that we have no obligation of knowing who is Moshiach but we do have the obligation to prevent arguments (especially about this topic) Our center of Avoda should be concentrating on performing the Mitzvot 100%, learning Torah as much as possible, doing acts of kindness and charity and most important, educating other Jews about Torah and Mitzvot and preparing ourselves and others (including non Jews) for the coming of Moshiach. May we merit to see the coming of Moshiach right NOW with our own eyes All the best, Rabbi Alon Anava